State of the Beach/State Reports/PR/Beach Erosion
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The report "State Coastal Program Effectiveness in Protecting Natural Beaches, Dunes, Bluffs, and Rock Shores" (T. Bernd-Cohen and M. Gordon), Coastal Management 27:187-217, 1999, states that the amount of Puerto Rico's shoreline that is critically eroding is unknown. However, there is no question that it is severe, especially after recent the recent devastation caused by Hurricane Maria. Read "You build castles on the sand, they will fall into the sea" article for more information.
All sandy beaches in Puerto Rico are threatened as source watershed disruption blocks the delivery of sand from river sources. Industrial sand removal operations have permanently removed fragile sand dune ecosystems around the island. Loss of over one meter of sandy beach face is not uncommon on many beaches in Puerto Rico.
Jack Morelock, with the Geological Oceanography Program of the Department of Marine Sciences, University of Puerto Rico, Mayaguez has a great Website Coastal Morphology & the Shoreline of Puerto Rico with tons of information about the coast of Puerto Rico. The beach erosion section on this Website contains the following discussion:
Construction activities have crowded close to the shoreline because of limited land areas and reduced construction costs. This has not only aggravated the erosional process, but has put valuable new property in areas of natural erosion. This has in turn created the need to institute urgent and expensive protective techniques to protect the investment. These remedies may have effects not immediately recognized. Construction close to the beach south of Mayaguez Harbor was being rapidly endangered by erosion. Riprap was emplaced to protect this property, which then cut off a source of sand -- natural coastal erosion -- from the area to the south. The next step was riprap protection for houses to the south which were being threatened by the erosion generated by the riprap. As the problem moved south the entire beach was eventually replaced with riprap. The coast is now stabilized, with a basic change in coastal classification from sandy beach to rocky shoreline, man-made.
The Website contains numerous references to technical papers that have been published describing the coastal features of Puerto Rico, including
- Coastal Erosion in Puerto Rico (1978)
- Beach Sand Budget for Western Puerto Rico
- Working Towards a Beach Budget for Northwestern Puerto Rico
Shoreline of Puerto Rico gives an overview of the coastal geology and beach dynamics in Puerto Rico. It also contains several images of Puerto Rico’s shoreline.
More from the same author on coastal erosion around Puerto Rico: http://geology.uprm.edu/Morelock/GEOLOCN_/coast/erosionPR.htm
A USGS publication and Gravel Resources of Puerto Rico states:
"The sand and gravel resources of Puerto Rico contribute significantly to the economy of the island as they are crucial ingredients in construction and recreation. Despite newly-imposed regulations prohibiting mining of beach sands, the strength of the associated underground economy is sufficiently strong to limit enforcement of the regulations. Consequently, beaches are eroding quickly causing significant damage to the environment and delicate ecosystems. New resources of sand and gravel would allow beaches to be nourished and construction activities to be supplied." -Rafael Rodriguez, U.S. Geological Survey
The United States Geological Survey (USGS) commenced work on a coastal erosion study in Rincón in December 2005. As part of these efforts, USGS staff held a forum at the Cooperativa de Ahorro y Credito de Rincón with representatives of the Municipality, Commonwealth agencies, and community members to discuss the project. The presentations focused not only on the existing project, but also included a discussion of what other studies might be considered as Rincón searches for solutions to its serious coastal erosion crisis that threatens beach access, quality of life, marine species, including sea turtles, and may jeopardize tourism - the motor of the local economy.
The aim of the project is to survey the shoreline position between Punta Higüero and Punta Cadena along the west coast of Puerto Rico and compare the results to the most recent GPS-based survey conducted in 1994. Thieler et al. (1995) used the 1994 field survey data, along with analysis of historical shoreline positions from aerial photography, for a comprehensive shoreline change analysis. Their results indicated large areas of severe erosion (up to approximately 3.0 m/yr) and dramatic changes in nearshore and coastal sedimentation, likely due to the marina construction at Punta Ensenada (Thieler et al., 1995). The proposed GPS-based survey of the most recent shoreline position will evaluate the shoreline change trends along this section of the coast over the past eleven years, and assess the effects of the Punta Ensenada marina on the downdrift shoreline.
Dr. E. Robert Thieler of the US Geological Survey is the principal author of Historical Shoreline Changes at Rincon, Puerto Rico, 1936-2006.
An interesting article by the USGS concerns the effects of Hurricane Hugo on Puerto Rico. Another USGS Website describes this and other USGS projects in Puerto Rico. It has a brief discussion of beach erosion over the past 40 years at and south of the Little Malibu/Marina de Rincon. The report includes an analysis of beach erosion for the stretch of beach roughly covered by the Rincon Quadrangle (Punta Higueras to south of the Town of Rincon).
A 1996 UNESCO/Puerto Rico Sea Grant Report discusses beach erosion response to hurricanes in the eastern Caribbean Islands. Tropical Storm Iris and Hurricanes Luis and Marilyn passed through the eastern Caribbean Islands within the three-week period 26 August to 16 September 1995. All the islands from Grenada to Puerto Rico were impacted by these storms. In 1989, Hurricane Hugo had passed through the eastern Caribbean islands along a similar track.
The 1989 and 1995 hurricanes caused severe beach erosion in the islands; beach volumes decreased on average by 28% following the 1995 storms. There was, however, considerable variation from beach to beach: Some beaches actually accreted, while others were totally stripped of sand. The hurricanes also caused retreat of the land edge or sand dunes behind the beach. This coastline retreat is viewed as a "permanent" change. Within 40 kilometers of the center of Hurricane Luis, the average coastline retreat varied between 5 meters and 18 meters, with the maximum recorded coastline retreat 30 meters. Between 40 and 180 kilometers of the center of Hurricane Luis the coastline retreat was between 2 and 5 meters.
There was a clear relationship between the proximity of the hurricane center and the amount of beach erosion. Nevertheless, other factors which influenced the severity of the erosion include the characteristics of a particular hurricane, coastline shape, width of the offshore shelf, and local features such as coral reefs. Similar magnitudes and patterns of beach erosion occurred when islands were impacted by both the 1989 and 1995 hurricanes.
Major beach recovery took place, particularly within eight months of Hurricane Luis. Analysis of data from Hurricane Hugo showed that beach recovery continued at a slower rate for two to three years after the hurricane, and that the beaches did not recover to their pre-hurricane levels.
In view of predictions of increased hurricane activity in the next two decades, it was recommended that coastal development setbacks be reviewed in each island and, if necessary, amended. The study also noted that conservation of beaches is fundamental to the economic and social well being of all citizens of the eastern Caribbean Islands. Tourism, the region's primary industry, is dependent on the beaches, which form an integral part of each island's heritage.
Some information on erosion and coastal hazards is available through Puerto Rico Sea Grant. The Puerto Rico Sea Grant College Program is devoted to the conservation and sustainable use of coastal and marine resources in Puerto Rico, the U.S. Virgin Islands and the Caribbean region. Their mission is two-fold: to conduct excellent scientific research in the areas of water quality, fisheries and mariculture, seafood safety, marine recreation and coastal tourism, coastal hazards and coastal communities economic development; and to apply their scientific knowledge to solve a variety of problems communities of users in Puerto Rico face every day.
General Reference Documents
The Heinz Center's Evaluation of Erosion Hazards, conducted for the Federal Emergency Management Agency (FEMA), studied the causes of coastal erosion hazards and proposed a variety of national and regional responses. The study, published in April 2000, concentrates on the economic impacts of erosion response policies as well as the cost of erosion itself to homeowners, businesses, and governmental entities.
A NOAA website that has graphs of sea level data for many coastal locations around the country over the last 40 to 50 years and projections into the future is Sea Levels Online.
NOAA Shoreline Website is a comprehensive guide to national shoreline data and terms and is the first site to allow vector shoreline data from NOAA and other federal agencies to be conveniently accessed and compared in one place. Supporting context is also included via frequently asked questions, common uses of shoreline data, shoreline terms, and references. Many NOAA branches and offices have a stake in developing shoreline data, but this is the first-ever NOAA Website to provide access to all NOAA shorelines, plus data from other federal agencies. The site is a culmination of efforts of NOAA and several offices within NOS (including NOAA’s Coastal Services Center, National Geodetic Survey, Office of Coast Survey, Special Projects Office, and Office of Ocean and Coastal Resource Management) and other federal agencies to provide coastal resource managers with accurate and useful shoreline data.
A related site launched in 2008 is NOAA Coastal Services Center's Digital Coast, which can be used to address timely coastal issues, including land use, coastal conservation, hazards, marine spatial planning, and climate change. One of the goals behind the creation of the Digital Coast was to unify groups that might not otherwise work together. This partnership network is building not only a website, but also a strong collaboration of coastal professionals intent on addressing coastal resource management needs. Website content is provided by numerous organizations, but all must meet the site’s quality and applicability standards. More recently, NOAA Coastal Services Center has developed a Sea Level Rise and Coastal Flooding Impacts Viewer as part of its Digital Coast website. Being able to visualize potential impacts from sea level rise is a powerful teaching and planning tool, and the Sea Level Rise Viewer brings this capability to coastal communities. A slider bar is used to show how various levels of sea level rise will impact coastal communities. Completed areas include Mississippi, Alabama, Texas, Florida, and Georgia, with additional coastal counties to be added in the near future. Visuals and the accompanying data and information cover sea level rise inundation, uncertainty, flood frequency, marsh impacts, and socioeconomics.
Two Puerto Rico locations are shown on the NOAA Tides and Currents site under Other CO-OPS Stations.
Hazard Avoidance Policies/Erosion Response
See the Erosion Response section.
- ↑ Daniel Whiting, Puerto Rico Surfrider Chapter, written correspondence. April 2, 2001.
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